RESUMO
We present 2 diagnostically challenging cases of pediatric/adolescent relapsed/refractory aggressive mature B-cell non-Hodgkin lymphoma (B-NHL) within the spectrum of Burkitt lymphoma and diffuse large B-cell lymphoma and illustrate the different therapeutic regimens that are employed for pediatric and adult cancer centers. Both cases displayed varying-sized lymphoma cells with occasional single prominent nucleoli and heterogeneous BCL2 expression. Cytogenetics revealed complex karyotypes with t(8:14)(q24.2;q32) and IGH::MYC rearrangement by FISH. Next generation sequencing revealed deleterious TP53 and MYC mutations. We concluded that both could be diagnosed as "DLBCL-NOS with MYC rearrangement" using the current pathologic classifications, 2022 International Consensus Classification (ICC) and World Health Organization Classifications of Haematolymphoid Tumors (WHO-HAEM5). This report illustrates diagnostic challenges and treatment dilemmas that may be encountered, particularly for adolescent and young adults (AYA).
Assuntos
Linfoma de Burkitt , Linfoma Difuso de Grandes Células B , Proteínas Proto-Oncogênicas c-bcl-2 , Translocação Genética , Humanos , Linfoma de Burkitt/genética , Linfoma de Burkitt/diagnóstico , Linfoma de Burkitt/patologia , Linfoma de Burkitt/metabolismo , Linfoma de Burkitt/terapia , Linfoma Difuso de Grandes Células B/genética , Linfoma Difuso de Grandes Células B/diagnóstico , Linfoma Difuso de Grandes Células B/patologia , Linfoma Difuso de Grandes Células B/terapia , Linfoma Difuso de Grandes Células B/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Adolescente , Masculino , Criança , Feminino , Diagnóstico Diferencial , Biomarcadores Tumorais/genética , Biomarcadores Tumorais/metabolismo , Cromossomos Humanos Par 14/genética , Recidiva Local de Neoplasia/patologia , Recidiva Local de Neoplasia/genética , Cromossomos Humanos Par 8/genéticaRESUMO
Risk stratification and molecular targeting have been key to increasing cure rates for pediatric cancers in high-income countries. In contrast, precise diagnosis in low-resource settings is hindered by insufficient pathology infrastructure. The Global HOPE program aims to improve outcomes for pediatric cancer in Sub-Saharan Africa (SSA) by building local clinical care and diagnostic capacity. This study aimed to assess the feasibility of implementing molecular assays to improve leukemia diagnoses in SSA. Custom NanoString nCounter gene fusion assays, previously validated in the US, were used to test samples from suspected leukemia patients. The NanoString platform was chosen due to relatively low cost, minimal technical and bioinformatics expertise required, ability to test sub-optimal RNA, and rapid turnaround time. Fusion results were analyzed blindly, then compared to morphology and flow cytometry results. Of 117 leukemia samples, 74 were fusion-positive, 30 were negative, 7 were not interpretable, and 6 failed RNA quality. Nine additional samples were negative for leukemia by flow cytometry and negative for gene fusions. All 74 gene fusions aligned with the immunophenotype determined by flow cytometry. Fourteen samples had additional information available to further confirm the accuracy of the gene fusion results. The testing provided a more precise diagnosis in >60% of cases, and 9 cases were identified that could be treated with an available tyrosine kinase inhibitor, if detected at diagnosis. As risk-stratified and targeted therapies become more available in SSA, implementing this testing in real-time will enable the treatment of pediatric cancer to move toward incorporating risk stratification for optimized therapy.
RESUMO
The survival rate of pediatric acute myeloid leukemia (pAML) is currently around 60%. While survival has slowly increased over the past few decades, the development of novel agents likely to further improve survival for this heterogeneous patient population has been limited by gaps in the pAML pre-clinical pipeline. One of the major hurdles in evaluating new agents for pAML is the lack of pAML patient-derived xenograft (PDX) models. Unlike solid tumors and other types of leukemias, AML is notoriously hard to establish in mouse models, likely due in part to the need for specific human microenvironment elements. Our laboratory at TCH/BCM addressed this gap by establishing a systematic PDX workflow, leveraging advanced immunodeficient hosts and capitalizing on our high volume of pAML patients and close coordination between labs and clinical sections. Patients treated at TCH are offered the chance to participate in specimen banking protocols that allow blood and bone marrow collection as well as the collection of relevant clinical data. All patients who consent and have samples available are trialed for PDX development. In addition, samples from the Children's Oncology Group (COG) are also trialed for PDX generation. Serially transplanting PDX models are validated using short tandem repeat (STR) and characterized using both targeted DNA/RNA next generation sequencing and RNAseq. As of March 2023, this systematic approach has resulted in 26 serially transplanting models. Models have been shared with requesting labs to facilitate external pAML pre-clinical studies. Available PDX models can be located through the BCM PDX Portal. We expect our growing PDX resource to make a significant contribution to expediting the testing of promising novel therapeutics for pAML.